The invention relates to systems for applying compressive pressures against a patient""s limb, specifically to a miniaturized, automatic portable ambulant system.
Various conventional compression devices are known for applying compressive pressure to a patient""s limb. These types of devices are used to assist in a large number of medical indications, mainly the prevention of deep vein thrombosis (DVT), vascular disorders, reduction of edemas and the healing of wounds. Prior art devices are typically divided into two main segments: 1) a hospital segment, in which they are used mainly for the prevention of DVT in patients with high risk for developing the same, and 2) a home segment, in which they are mainly used to treat severe lymphedema.
Although showing high clinical efficacy in treating the above clinical indication, prior art devices share the following disadvantages. First, they use the conventional main power supply (wall outlet), and thus impose total confinement on the patient during treatment. The pump unit is heavy (5-15 pounds), which makes it hard to maneuver and place in the vicinity of the patients. The pump unit is big and thus creates a storage problem, specifically in hospitals, in which a few units are stationed, usually in a special storage room. The sleeve is big and ungainly, and thus restricts the movement of the limb it encompasses and imposes an aesthetic discomfort. In addition, the use of multiple cells demands the use of multiple conduits (usually one for each cell) making the whole system more cumbersome and harder to maneuver. All of the aforementioned disadvantages result in poor patient and therapist (mainly nurses) compliant, resulting in that the devices are used for treatment only to the most severe cases of the medical indications described above.
Prior art devices need to be as big and use the conventional electrical outlets for the power supply as they all use the same basic shape of inflatable bladders for their sleeves. These devices use substantial amounts of fluid (usually air) in order to inflate the sleeve and create the desired pressure at a timely manner (between 0.25-10 seconds per chambre). As a consequence, the devices need a large compressor that require high current supply, which forces their connection to the electrical outlets for power supply. The same follows with respect to the need for relatively large components in the prior art devices, such as solenoids, air conduits etc.
The need for a small ambulant/portable aesthetic device has long been recognized by the industry, as evident from prior patents of leading companies in this field. Patents such as U.S. Pat. Nos. 5,795,312, 5,626,556, 4,945,905, and 5,354,260, as well as EP 0861652, and others, are concerned with using less air to inflate the sleeves, easier handling, especially with the connection of the pump unit to the patient bed, and all of the other disadvantages previously discussed.
A step in this direction was the introduction of foot pumps. Still, as scientists and engineers were fixed on improving the pumps (their flow rate, power consumption etc.) and not on improving the use of the pumped air (as described in the related U.S. patent applications of the applicant, that enables one to accomplish the same pressures in the same timely manner and the same therapeutic goals with about {fraction (1/10)} of the volume of air prior art devices need), no major breakthrough in the size of the sleeve/ pump unit, its power source or mobility during use were accomplished until the present invention. A small, ambulant, portable device will achieve the following needs that prior art devices could not accomplish. First, patients will gain the freedom of movement without treatment interruption. Currently, patients in hospitals which are connected to prior art devices for 5 consecutive days following their operation cannot move from their beds unless treatment is interrupted, e.g., each time the patient needs to use the bathroom or move around, the nurse has to come unhook the patient from the device and afterwards reconnect the patient to the device. Home users of prior art devices (mainly patients suffering from acute lymphedema) have to confine themselves to one place during treatment and are restricted from basic mobility needs such as the use of bathroom, opening the door, etc. Second, it will be easy to use and handle. Currently, patients being discharged from the hospital are stopped from treatment by the device, although still considered under high risk for developing DVT, as the earlier described disadvantages (size, weight, mobility) of the devices makes them almost unsuitable for self use at home, especially when dealing with the elderly population. Nurses in the hospital are bothered by the need to connect and disconnect the many conduits most of the devices use and to carry and place the devices, from the storage room to the patient bed, back and forth. These are time consuming actions that need to be done whenever a new patient arrives, or if a fault arises in the device during operation or if the patient is moved for a short time from his or her bed. Third, it will eliminate the storage problem, with conventional devices there is a need for a storage room, mainly in the hospitals in which there are a few pump units and sleeves. Fourth, it will enable the user (mainly the home user) to get engaged in social activity during treatment. Conventional devices impose great aesthetic discomfort and thus restrict the home user from any social activity.
By achieving all the above needs, the new compression system will be suitable for use not only for severe cases of medical indication relating to the healing of wounds, reduction of edemas, vascular disorders and the prevention of DVT, but also to the mild cases, for whom, until now, the only alternate solution was the use of elastic stocking which are, clinically, inferior form of therapy compared with pneumatic compression systems.
In accordance with one embodiment of the invention, there is provided an improved system for applying pressure against a patient""s limb. The system introduces a miniature, battery operated (rechargeable), ambulant pump unit, the size and weight of a personal radio, connected to an inflatable sleeve for use on a limb. The system can operate independently of a fixed power source as it uses small rechargeable batteries. The system can also operate while connected to a conventional electrical outlet, at the time of such operation or at any other time it is connected to the electrical outlet, the system will automatically recharge itself.
The system provides a pump unit that can be carried around while operating, connected to an aesthetic flexible inflatable sleeve that can easily be concealed, for example, under trusses. The sleeve has a plurality of cells arranged longitudinally along the sleeve from the distal part of the limb to which it is applied, to its proximal part. Each cell is subdivided into two or more longitudinally extending confluent compartments that are inflated and deflated essentially simultaneously. The system has means for intermittently inflating the cells during periodic compression cycles, and means for intermittently connecting the cells to an exhaust port.
In one aspect of the invention, the pump unit can be operated alternatively as a foot pump, calf pump or a simultaneous foot and calf pump. In another aspect, a combination of self operated relief valves and check valves can be used for the inflation and deflation of the sleeve cells, thus achieving additional compactness and lower power consumption of the pump unit, and uses only one air conduit between the pump unit and the sleeve. In yet another aspect, while the system is connected to a conventional electrical power outlet, the rechargeable batteries can be bypassed and recharged only if necessary, thus expanding their life expectancy. Yet in another aspect, the pump unit can use an accumulator in order to speed the time needed for the inflation of each cell.
Accordingly, the invention provides a system for applying compressive pressure to a limb in which the pump unit is small, light weight, ambulant and can operate independent of electrical power supply outlets, and utilizes a small flexible inflatable sleeve placed on a treated limb, thus enabling the freedom of movement of the treated person. The portability of the system allows for easy handling, placement in the vicinity of the patient, storage, and does not disturb the patient or surroundings during treatment.
In a further aspect of the invention, only one conduit is used from the pump unit to the inflatable sleeve, regardless of the amount of cells in the sleeve, thus greatly simplifying connection to the sleeve and improving patient compliance as numerous conduits usually restrict movement. The configuration enables reduction in the size of the pump unit, reduces current consumption of the pump unit and allows for longer independent operation. In addition, the system can utilize a connector between the pump unit and the conduits to the sleeve that is able to decide the needed treatment, thus eliminating the risk of choosing the wrong treatment, especially when more than one limb is treated and the treatment is asymmetric.